At 5 a.m. Tuesday, Sandy, the 18th named storm of the season, was about 345 miles southwest of Kingston, Jamaica with sustained winds of 45 mph. After being nearly stationary for the last 12 hours, Sandy was crawling toward the north at 3 mph.

The system is predicted to angle northeast over Jamaica on Wednesday, move over Cuba on Thursday and arrive over the central Bahamas on Friday.

If that prediction holds, it would be about 400 miles east of Miami on Friday, its closest approach to the state.

The system still might come close enough to generate large swells, rough surf, gusty winds and heavy rains, starting on Thursday and continuing into the weekend, the National Weather Service in Miami said.

"As always, it's advised to not focus too much on the center location and eventual track, especially with late-season systems like this," he said, adding the large system might generate nasty weather far from its center.

The storm is expected to bring heavy rain to Jamaica, Cuba and Hispaniola over the next few days. A tropical storm watch has been issued for Jamaica.

With Sandy, the 2012 Atlantic season becomes the fourth busiest on record, tied with 1969, which also saw 18 named storms.

Ahead of this year: 2005 with 28 storms; 1933 with 21; and 2011, 2010, 1995 and 1887 with 19.